[BUG] No TX and very low audio level on RX/MONITOR

[hiddenvs]

Describe the bug
Transmit is disabled after flashing the radio with NUNU v20.5.
Always I press PTT only message appears "VOLT HIGH - TX DISABLE".

Details:

• Firmware version: NUNU v.20.5
• others: F LOCK = DEFAULT + 137-174 400-470
  (doesn't mather what is set, behavior is the same as described)

Radio is classic UV-K5 with 1600 mAh battery bought on Banggood.
Audio level is very low outside of FM radio or beep tone from keyboard.

[Nunu]

It is not a bug. Voltage is too high.
You might want to read Wiki on how to calibrate the battery or use a different battery.